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In a phase 2b trial involving patients with hypertriglyceridemia, the use of olezarsen (which targets APOC3 mRNA) for 6 months reduced triglyceride levels by approximately 50% as compared with placebo.

Mixed dyslipidaemia, characterised by elevated concentrations of circulating triglycerides and LDL cholesterol (LDL-C), is associated with an increased risk of atherosclerotic cardiovascular disease. Solbinsiran, a GalNAc-conjugated small interfering RNA targeting hepatic angiopoietin-like protein 3 (ANGPTL3), reduced triglycerides and LDL-C concentrations in a phase 1 study. This study aimed to assess the durability and efficacy of solbinsiran in reducing concentrations of atherogenic lipoproteins in adults with mixed dyslipidaemia. This double-blind, parallel-arm, randomised, placebo-controlled, phase 2 trial enrolled adults (aged ≥18 years) with mixed dyslipidaemia at 41 clinical research units across seven countries. Patients receiving moderate-intensity or high-intensity statins, and with concentrations of fasting triglycerides between 1·69 mmol/L and 5·64 mmol/L, LDL-C of at least 1·81 mmol/L, and non-HDL cholesterol of at least 3·36 mmol/L were included. Using an interactive web-response system, patients were randomly assigned (1:2:2:2) to receive either solbinsiran 100 mg, solbinsiran 400 mg, solbinsiran 800 mg, or placebo, by subcutaneous injection on days 0 and 90. Patients were followed up for at least 270 days. The primary outcome was percent change in apolipoprotein B (apoB) concentration from baseline to day 180 with solbinsiran compared with placebo, analysed under an efficacy estimand (in patients who received at least one dose of the study drug). This trial is completed and registered with ClinicalTrials.gov, NCT05256654. Of 585 patients screened, 205 patients were enrolled in the study between July 20, 2022, and March 4, 2024. Patients (111 [54%] female and 94 [46%] male; median age 57 years [IQR 49–65]) were randomly assigned to receive solbinsiran 100 mg (n=30), solbinsiran 400 mg (n=58), solbinsiran 800 mg (n=59), or placebo (n=58). At baseline, median concentrations were 111 mg/dL (IQR 96–130) for apoB, 2·64 mmol/L (2·06–3·29) for triglycerides, and 3·16 mmol/L (2·57–3·82) for LDL-C. The placebo-adjusted percent change in apoB concentration from baseline at day 180 was –2·8% (95% CI –15·5 to 11·9; p=0·69) for solbinsiran 100 mg; –14·3% (–23·6 to –3·9; p=0·0085) for solbinsiran 400 mg; and –8·3% (–18·3 to 2·9; p=0·14) for solbinsiran 800 mg. Solbinsiran administration was well tolerated, with a low incidence of adverse events. The number of patients with treatment-emergent adverse events was 18 [60%] of 30 patients in the solbinsiran 100 mg group, 30 [52%] of 58 patients in the solbinsiran 400 mg group, 26 [44%] of 59 patients in the solbinsiran 800 mg group, and 37 [65%] of 57 patients in the placebo group. Solbinsiran 400 mg reduced apoB in patients with mixed dyslipidaemia and was generally well tolerated. The impact of solbinsiran on cardiovascular outcomes remains to be investigated. Eli Lilly and Company.

Short-term studies indicate that bempedoic acid, an ATP citrate lyase inhibitor, reduces LDL cholesterol levels. In a 1-year trial, bempedoic acid added to maximally tolerated statin therapy did not lead to a higher incidence of adverse events than placebo and led to significantly lower LDL cholesterol levels.

Background: Observationally plasma apolipoprotein E (apoE) is positively associated with ischemic heart disease (IHD). A Mendelian randomization (MR) study suggesting apoE is unrelated to cardiovascular mortality did not consider specific isoforms. We used MR to obtain estimates of plasma apoE2, apoE3 and apoE4 on IHD, low-density lipoprotein (LDL) and high-density lipoprotein (HDL) cholesterol, triglycerides and apolipoprotein B (apoB). Methods: We obtained independent genetic instruments from proteome genome-wide association studies (GWAS) and applied them to large outcome GWAS. We used univariable MR to assess the role of each isoform and multivariable MR to assess direct effects. Results: In univariable MR, apoE4 was positively associated with IHD (odds ratio (OR) 1.05, 95% confidence interval (CI) 1.01 to 1.09), but apoE2 and apoE3 were less clearly associated. Using multivariable MR an association of apoE2 with IHD (OR 1.16, 95% CI 0.98 to 1.38) could not be excluded, and associations of apoE3 and apoE4 with IHD were not obvious. In univariable MR, apoE2 and apoE4 were positively associated with apoB, and a positive association of apoE2 with LDL cholesterol could not be excluded. Using multivariable MR apoE2 was positively associated with LDL cholesterol, and associations with apoB could not be excluded. After adjusting for apoB, no direct effects of apoE isoforms on IHD were evident. Conclusions: Plasma apoE2 and apoE4 may play a role in lipid modulation and IHD. Whether apoE could be a potential therapeutic target requires further clarification when larger genetic studies of apoE isoforms are available.

Improved understanding of lipoproteins, particles that transport lipids throughout the circulation, is vital to developing new treatments for the dyslipidemias associated with metabolic syndrome. Apolipoproteins are a key component of lipoproteins. Apolipoproteins are proteins that structure lipoproteins and regulate lipid metabolism through control of cellular lipid exchange. Constraints of cell culture and mouse models mean that there is a need for a complementary model that can replicate the complex in vivo milieu that regulates apolipoprotein and lipoprotein biology. Here, we further establish the utility of the genetically tractable and optically clear larval zebrafish as a model of apolipoprotein biology. Gene ancestry analyses were implemented to determine the closest human orthologs of the zebrafish apolipoprotein A-I (apoA-I), apoB, apoE and apoA-IV genes and therefore ensure that they have been correctly named. Their expression patterns throughout development were also analyzed, by whole-mount mRNA in situ hybridization (ISH). The ISH results emphasized the importance of apolipoproteins in transporting yolk and dietary lipids: mRNA expression of all apolipoproteins was observed in the yolk syncytial layer, and intestinal and liver expression was observed from 4-6 days post-fertilization (dpf). Furthermore, real-time PCR confirmed that transcription of three of the four zebrafish apoA-IV genes was increased 4 hours after the onset of a 1-hour high-fat feed. Therefore, we tested the hypothesis that zebrafish ApoA-IV performs a conserved role to that in rat in the regulation of food intake by transiently overexpressing ApoA-IVb.1 in transgenic larvae and quantifying ingestion of co-fed fluorescently labeled fatty acid during a high-fat meal as an indicator of food intake. Indeed, ApoA-IVb.1 overexpression decreased food intake by approximately one-third. This study comprehensively describes the expression and function of eleven zebrafish apolipoproteins and serves as a springboard for future investigations to elucidate their roles in development and disease in the larval zebrafish model.

Apolipoprotein B (ApoB) and ApoE have been shown to participate in the particle formation and the tissue tropism of hepatitis C virus (HCV), but their precise roles remain uncertain. Here we show that amphipathic α-helices in the apolipoproteins participate in the HCV particle formation by using zinc finger nucleases-mediated apolipoprotein B (ApoB) and/or ApoE gene knockout Huh7 cells. Although Huh7 cells deficient in either ApoB or ApoE gene exhibited slight reduction of particles formation, knockout of both ApoB and ApoE genes in Huh7 (DKO) cells severely impaired the formation of infectious HCV particles, suggesting that ApoB and ApoE have redundant roles in the formation of infectious HCV particles. cDNA microarray analyses revealed that ApoB and ApoE are dominantly expressed in Huh7 cells, in contrast to the high level expression of all of the exchangeable apolipoproteins, including ApoA1, ApoA2, ApoC1, ApoC2 and ApoC3 in human liver tissues. The exogenous expression of not only ApoE, but also other exchangeable apolipoproteins rescued the infectious particle formation of HCV in DKO cells. In addition, expression of these apolipoproteins facilitated the formation of infectious particles of genotype 1b and 3a chimeric viruses. Furthermore, expression of amphipathic α-helices in the exchangeable apolipoproteins facilitated the particle formation in DKO cells through an interaction with viral particles. These results suggest that amphipathic α-helices in the exchangeable apolipoproteins play crucial roles in the infectious particle formation of HCV and provide clues to the understanding of life cycle of HCV and the development of novel anti-HCV therapeutics targeting for viral assembly.

Experimental studies provided evidence about mechanisms by which cholesterol, especially high density lipoprotein cholesterol (HDL-C), could influence carcinogenesis, notably through antioxidant and anti-inflammatory properties. However, prospective studies that investigated the associations between specific lipid metabolism biomarkers and cancer risk provided inconsistent results. The objective was to investigate the prospective associations between total cholesterol (T-C), HDL-C, low density lipoprotein cholesterol, apolipoproteins A1 (apoA1) and B, and triglycerides and overall, breast and prostate cancer risk. Analyses were performed on 7,557 subjects of the Supplementation en Vitamines et Mineraux Antioxydants Study, a nationwide French cohort study. Biomarkers of lipid metabolism were measured at baseline and analyzed regarding the risk of first primary incident cancer (N = 514 cases diagnosed during follow-up, 1994-2007), using Cox proportional hazards models. T-C was inversely associated with overall (HR1(mmol/L increment) = 0.91, 95 % CI 0.82-1.00; P = 0.04) and breast (HR1mmol/L increment = 0.83, 95 % CI 0.69-0.99; P = 0.04) cancer risk. HDL-C was also inversely associated with overall (HR1mmol/L increment = 0.61, 95 % CI 0.46-0.82; P = 0.0008) and breast (HR1mmol/L increment = 0.48, 95 % CI 0.28-0.83; P = 0.009) cancer risk. Consistently, apoA1 was inversely associated with overall (HR1g/L increment = 0.56, 95 % CI 0.39-0.82; P = 0.003) and breast (HR1g/L increment = 0.36, 95 % CI 0.18-0.73; P = 0.004) cancer risk. This prospective study suggests that pre-diagnostic serum levels of T-C, HDL-C and ApoA1 are associated with decreased overall and breast cancer risk. The confirmation of a role of cholesterol components in cancer development, by further large prospective and experimental studies, may have important implications in terms of public health, since cholesterol is already crucial in cardiovascular prevention.

Activation of Peroxisome Proliferator–Activated Receptor (PPAR)δ Promotes Reversal of Multiple Metabolic Abnormalities, Reduces Oxidative Stress, and Increases Fatty Acid Oxidation in Moderately Obese Men Ulf Risérus 1 , Dennis Sprecher 2 , Tony Johnson 2 , Eric Olson 2 , Sandra Hirschberg 2 , Aixue Liu 3 , Zeke Fang 4 , Priti Hegde 5 , Duncan Richards 6 , Leli Sarov-Blat 5 , Jay C. Strum 5 , Samar Basu 7 , Jane Cheeseman 1 , Barbara A. Fielding 1 , Sandy M. Humphreys 1 , Theodore Danoff 3 , Niall R. Moore 8 , Peter Murgatroyd 9 , Stephen O'Rahilly 10 , Pauline Sutton 1 , Tim Willson 11 , David Hassall 12 , Keith N. Frayn 1 and Fredrik Karpe 1 1 Oxford Centre for Diabetes, Endocrinology and Metabolism, University of Oxford, Oxford, U.K 2 Cardiovascular and Urogenital Center for Excellence in Drug Discovery, GlaxoSmithKline, King of Prussia, Pennsylvania 3 Human Target Validation, Cardiovascular and Urogenital Center for Excellence in Drug Discovery, GlaxoSmithKline, King of Prussia, Pennsylvania 4 Statistics, GlaxoSmithKline, King of Prussia, Pennsylvania 5 Clinical Pharmacology and Discovery Medicine/Cardiovascular and Urogenital (CPDM CVU) Unit, GlaxoSmithKline, King of Prussia, Pennsylvania 6 Addenbrooke's Centre for Clinical Investigation (ACCI) Unit, GlaxoSmithKline, Cambridge, U.K 7 Department of Public Health, University of Uppsala, Uppsala, Sweden 8 Department of Radiology, Churchill Hospital, University of Oxford, Oxford, U.K 9 Wellcome Trust Clinical Research Facility, Addenbrooke's Hospital, Cambridge, U.K 10 Department of Clinical Biochemistry and Medicine, University of Cambridge, Cambridge, U.K 11 GlaxoSmithKline, Research Triangle Park, North Carolina 12 GlaxoSmithKline, Stevenage, U.K Address correspondence and reprint requests to Dr. F. Karpe, Churchill Hospital, Oxford OX3 7LJ, U.K. E-mail: fredrik.karpe{at}ocdem.ox.ac.uk Abstract OBJECTIVE— Pharmacological use of peroxisome proliferator–activated receptor (PPAR)δ agonists and transgenic overexpression of PPARδ in mice suggest amelioration of features of the metabolic syndrome through enhanced fat oxidation in skeletal muscle. We hypothesize a similar mechanism operates in humans. RESEARCH DESIGN AND METHODS— The PPARδ agonist (10 mg o.d. GW501516), a comparator PPARα agonist (20 μg o.d. GW590735), and placebo were given in a double-blind, randomized, three-parallel group, 2-week study to six healthy moderately overweight subjects in each group. Metabolic evaluation was made before and after treatment including liver fat quantification, fasting blood samples, a 6-h meal tolerance test with stable isotope fatty acids, skeletal muscle biopsy for gene expression, and urinary isoprostanes for global oxidative stress. RESULTS— Treatment with GW501516 showed statistically significant reductions in fasting plasma triglycerides (−30%), apolipoprotein B (−26%), LDL cholesterol (−23%), and insulin (−11%), whereas HDL cholesterol was unchanged. A 20% reduction in liver fat content ( P < 0.05) and 30% reduction in urinary isoprostanes ( P = 0.01) were also observed. Except for a lowering of triglycerides (−30%, P < 0.05), none of these changes were observed in response to GW590735. The relative proportion of exhaled CO 2 directly originating from the fat content of the meal was increased ( P < 0.05) in response to GW501516, and skeletal muscle expression of carnitine palmitoyl-transferase 1b ( CPT1b ) was also significantly increased. CONCLUSIONS— The PPARδ agonist GW501516 reverses multiple abnormalities associated with the metabolic syndrome without increasing oxidative stress. The effect is probably caused by increased fat oxidation in skeletal muscle. Apo, apolipoprotein AST, aspartate aminotransferase AUC, area under the curve γGT, γ-glutamyltransferase LCM, laser capture microdissection LPL, lipoprotein lipase MRI, magnetic resonance imaging NEFA, nonesterified fatty acid TTR, tracer-to-tracee ratio Footnotes Published ahead of print at http://diabetes.diabetesjournals.org on 16 November 2007. DOI: 10.2337/db07-1318. U.R. and D.S. contributed equally to this work. Additional information for this article can be found in an online appendix at http://dx.doi.org/10.2337/db07-1318 . The costs of publication of this article were defrayed in part by the payment of page charges. This article must therefore be hereby marked “advertisement” in accordance with 18 U.S.C. Section 1734 solely to indicate this fact. Accepted November 10, 2007. Received September 14, 2007. DIABETES

Genetic variants at the SORT1 locus in humans, which cause increased SORT1 expression in the liver, are significantly associated with reduced plasma levels of LDL cholesterol and apolipoprotein B (apoB). However, the role of hepatic sortilin remains controversial, as genetic deletion of sortilin in mice has resulted in variable and conflicting effects on apoB secretion. Here, we found that Sort1-KO mice on a chow diet and several Sort1-deficient hepatocyte lines displayed no difference in apoB secretion. When these models were challenged with high-fat diet or ER stress, the loss of Sort1 expression resulted in a significant increase in apoB-100 secretion. Sort1-overexpression studies yielded reciprocal results. Importantly, carriers of SORT1 variant with diabetes had larger decreases in plasma apoB, TG, and VLDL and LDL particle number as compared with people without diabetes with the same variants. We conclude that, under basal nonstressed conditions, loss of sortilin has little effect on hepatocyte apoB secretion, whereas, in the setting of lipid loading or ER stress, sortilin deficiency leads to increased apoB secretion. These results are consistent with the directionality of effect in human genetics studies and suggest that, under stress conditions, hepatic sortilin directs apoB toward lysosomal degradation rather than secretion, potentially serving as a quality control step in the apoB secretion pathway in hepatocytes.

Background APOBEC-1 complementation factor (A1CF) and Apolipoprotein B mRNA editing enzyme, catalytic polypeptide-1 (APOBEC-1) constitute the minimal proteins necessary for the editing of apolipoprotein B (apoB) mRNA in vitro. Unlike APOBEC-1 and apoB mRNA, the ubiquitous expression of A1CF in human tissues suggests its unique biological significance, with various factors such as protein kinase C, thyroid hormones, and insulin regulating the activity and expression of A1CF. Nevertheless, few studies have provided an overview of this topic. Objective We conducted a literature review to describe the molecular mechanisms of A1CF and its relevance to human diseases. Method In the PubMed database, we used the keywords ‘A1CF’ and ‘APOBEC-1 complementation factor’ to collect peer-reviewed articles published in English from 2000 to 2023. Two authors independently reviewed the articles and reached the consensus. Result After reviewing 127 articles, a total of 61 articles that met the inclusion criteria were included in the present review. Studies revealed that A1CF is involved in epigenetic regulation of reproductive cells affecting embryonic development, and that it is closely associated with the occurrence of gout due to its editing properties on apoB. A1CF can also affect the process of epithelial-mesenchymal transition in renal tubular epithelial cells and promote liver regeneration by controlling the stability of IL-6 mRNA, but no influence on cardiac function was found. Furthermore, increasing evidence suggests that A1CF may promote the occurrence and development of breast cancer, lung cancer, renal cell carcinoma, hepatocellular carcinoma, endometrial cancer, and glioma. Conclusion This review clarifies the association between A1CF and other complementary factors and their impact on the development of human diseases, aiming to provide guidance for further research on A1CF, which can help treat human diseases and promote health.